1. Field of the Invention
The present invention relates to an imaging device, more specifically relates to an imaging device having at least one optical element which moves in a direction non-parallel to a photographing optical axis.
2. Description of the Related Art
In a retractable type of photographic lens using no mirrors or prisms as refractors for refracting an optical axis of a photographing optical system (photographing optical axis), it is generally impossible to make the length of the photographic lens, in a retracted state, shorter than the sum of the thickness of the optical elements of the photographing optical system in the optical axis direction. Nevertheless, there has been a demand for a further reduction in length of the retracted photographic lens to achieve an extra-short photographic lens. As a solution to this demand, the assignee of the prevent invention has proposed a zoom lens whose length, in a retracted state, is further reduced by radially retracting a part of the photographing optical system away from the photographing optical axis thereof. This zoom lens is disclosed in United States Patent Publication No. US2003/0156832 A1.
In addition, an imaging device having an optical image stabilizer in which a part of a photographing optical system is moved in directions perpendicular to an optical axis of the photographing optical system to counteract image shake is known in the art.
In the imaging device, in which a part of a photographing optical system is retracted away from the photographing optical axis thereof, and the imaging device, in which a part of a photographing optical system is moved in directions perpendicular to an optical axis thereof to counteract image shake, an optical element of the photographing optical system moves in a direction non-parallel to the optical axis of the photographing optical system, and accordingly, such a movable optical element is required to be precisely positioned with a high degree of positioning accuracy so that the optical performance of the photographing optical system of the imaging device does not deteriorate due to improper positioning of the movable optical element.